US20020179161A1 - Low slip steering system and improved fluid controller therefor - Google Patents

Low slip steering system and improved fluid controller therefor Download PDF

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Publication number
US20020179161A1
US20020179161A1 US09/870,024 US87002401A US2002179161A1 US 20020179161 A1 US20020179161 A1 US 20020179161A1 US 87002401 A US87002401 A US 87002401A US 2002179161 A1 US2002179161 A1 US 2002179161A1
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US
United States
Prior art keywords
fluid
valving
controller
normal operating
port
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US09/870,024
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English (en)
Inventor
William Novacek
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eaton Corp
Original Assignee
Eaton Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eaton Corp filed Critical Eaton Corp
Priority to US09/870,024 priority Critical patent/US20020179161A1/en
Assigned to EATON CORPORATION reassignment EATON CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NOVACEK, WILLIAM J.
Priority to EP20020011954 priority patent/EP1262393B1/de
Priority to JP2002155851A priority patent/JP4122473B2/ja
Priority to DE2002607927 priority patent/DE60207927T2/de
Priority to US10/278,953 priority patent/US6769249B2/en
Publication of US20020179161A1 publication Critical patent/US20020179161A1/en
Abandoned legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
    • B62D5/09—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle characterised by means for actuating valves
    • B62D5/093—Telemotor driven by steering wheel movement
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/86493—Multi-way valve unit
    • Y10T137/86574—Supply and exhaust
    • Y10T137/86638—Rotary valve
    • Y10T137/86646—Plug type
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/86493—Multi-way valve unit
    • Y10T137/86574—Supply and exhaust
    • Y10T137/86638—Rotary valve
    • Y10T137/86646—Plug type
    • Y10T137/86662—Axial and radial flow

Definitions

  • the present invention relates to fluid controllers for use in vehicle hydrostatic power steering systems, and more particularly, to such controllers which are to be used with fluid pressure operated steering actuators of the type which are likely to have noticeable leakage, from the inlet port to the outlet port of the actuator.
  • the present invention may be utilized in a hydrostatic power steering system in which the steering actuator is a linear cylinder (either single or double rod end), it is especially advantageous when utilized in a system in which the steering actuator is a rotary motor, and will be described in connection therewith.
  • rotary motors which could be utilized as the steering actuator would be a gear motor, or a vane motor, or possibly a gerotor motor of the fixed axis type.
  • the invention is especially advantageous when used with such a motor as the steering actuator for reasons which will become apparent subsequently.
  • the steering actuator defines an inlet and an outlet which are connected to the control fluid ports of a fluid controller, which is also typically referred to as a steering control unit (SCU).
  • SCU steering control unit
  • the steering actuator receives at its inlet a flow of metered, pressurized fluid from the SCU, which results in an output motion which, in turn, results in appropriate movement of the steered wheels.
  • the steering actuator is a rotary motor, there is likely to be the potential for a noticeable amount of internal leakage between the inlet and the outlet, effectively bypassing the rotating group.
  • the amount of leakage which can or does occur during normal steering operations does not represent a significant problem in terms of the overall performance of the steering system.
  • a typical fluid controller of the type to which the present invention relates includes some sort of controller valving defining a neutral position (when there is no steering input), a normal operating position (when normal steering is occurring) and a maximum displacement position, i.e., the maximum opening (flow area) of the valving.
  • controller valving defining a neutral position (when there is no steering input), a normal operating position (when normal steering is occurring) and a maximum displacement position, i.e., the maximum opening (flow area) of the valving.
  • the controller valving is typically displaced to the maximum displacement condition.
  • the conventional neutral return spring which is present in most such fluid controllers, tends to return the valving toward the neutral position, but is at its fully deflected condition when the valving is in the maximum displacement condition.
  • Fluid controllers of the type which can utilize the present invention typically include some sort of fluid actuated arrangement for imparting follow-up movement to the controller valving, tending to return the valving from its normal operating position toward its neutral position.
  • the fluid actuated arrangement is a fluid meter which comprises a gerotor gear set.
  • the gerotor gear set includes an internally toothed ring and an externally toothed star, disposed eccentrically within the ring.
  • One possible solution to the apparent slip problem discussed above is to increase the tip clearance of the teeth in the gerotor gear set, thus communicating some flow through the fluid meter to the control fluid port, to compensate for the leakage within the actuator.
  • feed-through such an increase in the tip clearance within the gerotor gears has been found to permit a condition known as “feed-through” in which there is a flow of fluid through the fluid meter even at times when such is not desired.
  • a fluid controller operable to control the flow of fluid from a source of pressurized fluid to a fluid pressure operated device having an inlet and an outlet and defining a fluid leakage path therebetween.
  • the fluid controller is of the type including a housing defining an inlet port for connection to the source of pressurized fluid, a return port for connection to a system reservoir, and a control port for connection to the inlet of the fluid pressure operated device.
  • the controller includes valving disposed in the housing and defining a neutral position, a normal operating position, and a maximum displacement position.
  • the housing and the valving cooperate to define a main fluid path providing fluid communication between the inlet port and the control port when the valving is in the normal operating position.
  • the controller includes a fluid actuated means for imparting follow up movement to the valving, tending to return the valving from its normal operating position toward the neutral position, the follow up movement being proportional to the volume of fluid flow through the main fluid path.
  • the main fluid path includes a first variable flow control orifice having a minimum flow area when the valving is in the neutral position, and an increasing flow area as the valving is displaced through the normal operating position toward the maximum displacement position.
  • the improved fluid controller is characterized by the valving defining a fluid bleed passage having an upstream portion in fluid communication with the main fluid path at a location upstream of the first variable flow control orifice, and a downstream portion in fluid communication with the main fluid path downstream of the fluid actuated means.
  • the fluid bleed passage includes a variable bleed orifice having a substantially zero flow area when the valving is in the neutral position and in the normal operating position. The variable bleed orifice begins to open as the valving approaches the maximum displacement position.
  • FIG. 1 is a hydraulic schematic of a hydrostatic power steering system including a fluid controller of the type which may utilize the present invention.
  • FIG. 2 is a greatly enlarged hydraulic schematic of the fluid controller of the present invention.
  • FIG. 3 is an axial cross-section of a fluid controller of the type to which the present invention relates.
  • FIG. 4 is a flat view of the spool valve of the fluid controller shown schematically in FIG. 2, including the present invention.
  • FIG. 5 is a flat view of the sleeve valve of the fluid controller shown schematically in FIG. 2, for use as part of the present invention
  • FIG. 6 is an enlarged, fragmentary overlay view of the valving shown in FIGS. 4 and 5, and with the valving in its neutral position.
  • FIG. 7 is an enlarged, fragmentary overlay view of the valving, similar to FIG. 6, but with the valving in its normal operating position, in a right turn.
  • FIG. 8 is an enlarged, fragmentary overlay view of the valving shown in FIG. 6, but with the valving in its maximum displacement position, and still in a right turn, and illustrating the operation of the present invention
  • FIG. 1 is a hydraulic schematic of a vehicle hydrostatic power steering system including a fluid controller of the type to which the present invention applies.
  • the system includes a source of pressurized fluid, generally designated 11 , which in the subject embodiment, and by way of example only, includes a fluid pump 13 and a load sensing priority type flow control valve 15 .
  • the fluid pump 13 is shown herein as a fixed displacement pump for ease of illustration, having its inlet connected to a system reservoir 17 .
  • the source 11 includes a pair of fluid outlets including a priority outlet 19 and an excess flow outlet 21 .
  • the excess flow outlet 21 is shown connected to an auxiliary load circuit, represented schematically by a variable orifice 23 .
  • the priority outlet 19 is connected by means of a conduit 25 to a fluid controller, generally designated 27 .
  • a fluid controller generally designated 27 .
  • the reference numeral “ 27 ” will be used throughout in reference to the fluid controller, even though the schematic representation in FIG. 1 and the axial cross-section in FIG. 3 do not actually illustrate the present invention.
  • the fluid controller 27 includes a housing 29 (see FIG. 3) which defines an inlet port 31 , to which is connected the conduit 25 .
  • the housing 29 also defines a return port 33 which is connected to the system reservoir 17 by means of a conduit 35 .
  • the housing 29 further defines a load signal port 37 (shown only in FIG. 1) from which a load signal 39 is communicated to the priority valve 15 in a manner well know to those skilled in the art.
  • the housing 29 of the fluid controller 27 also defines a pair of control (motor) fluid ports 41 and 43 which are connected to the opposite ports of a steering actuator, shown herein as comprising a rotary fluid pressure operated motor 45 .
  • a rotary fluid pressure operated motor 45 Assuming a right turn, the control port 41 is connected to a motor inlet 47 while a motor outlet 49 is connected to the other control port 43 .
  • the output of the rotary motor 45 is shown schematically in FIG. 1 as a shaft 51 which transmits torque (steering output motion) to a gear train, generally designated 53 , by means of which the rotation of the shaft 51 is transmitted into a higher torque rotation of a steered wheel support structure 55 .
  • a steered wheel 57 Attached rotatably to the support structure 55 , and driven thereby, is a steered wheel 57 , it being understood that, in a typical vehicle installation, there would be two of the steered wheels 57 , such that the structure associated with the steered wheel 57 , and shown in FIG. 1, would be duplicated. In some vehicle applications, there may be as many as four steered wheels, and the present invention is equally adaptable to such applications.
  • the fluid controller 27 includes controller valving, generally designated 61 , a general function of which is to control the flow of fluid from the inlet port 31 to the control port 41 (assuming a right turn), and at the same time, control the flow of returning fluid from the opposite control port 43 to the return port 33 .
  • controller valving generally designated 61
  • Such control of fluid flow within the fluid controller 27 is accomplished in response to rotation by the vehicle operator of a steering wheel, represented schematically in FIGS. 1 and 2 as an input 63 .
  • the fluid controller 27 may be of the general type illustrated and described in U.S. Pat. No. 5,638,864, assigned to the assignee of the present invention and incorporated herein by reference. More specifically, the fluid controller 27 includes controller valving 61 which is moveable from its neutral position (“N” in FIG. 2) to either a right turn position (“R” in FIG. 2) or a left turn position (“L” in FIG. 2). Those skilled in the art will understand that the normal operating positions of the controller valving 61 are those positions disposed immediately on either side of the neutral position N, in FIG. 2.
  • the pressurized fluid flowing through the valving 61 also flows through a fluid meter 65 , one function of which is to measure (meter) the proper amount of fluid to be communicated to the appropriate control port 41 or 43 .
  • the other function of the fluid meter 65 is to provide follow-up movement to the valving 61 , such that the valving is returned to its neutral position N after the desired amount of fluid has been communicated to the steering actuator. As is shown in FIGS. 1 and 2, such follow-up movement is achieved by means of a mechanical follow-up connection, from the fluid meter 65 to the valving 61 , the mechanical follow-up connection being shown schematically at 67 .
  • the controller valving 61 defines a plurality of variable orifices whenever the valving is moved from its neutral position N to one of its normal operating positions R or L. These variable orifices will be described in greater detail subsequently, in conjunction with the detailed description of FIGS. 6 through 8. Also shown schematically in FIG. 2 are two additional positions of the valving 61 which are not shown in FIG. 1, and which illustrate one aspect of the present invention. Adjacent the normal operating position in the right turn R is the right turn maximum displacement condition (“R-M”) and similarly, adjacent the normal operating position in the left turn L is the left turn maximum displacement position (“L-M”). These positions of the valving will also be described in greater detail, in connection with the description of FIG. 8.
  • the controller comprises several sections including the housing section 29 , a port plate 69 , a section comprising the fluid meter 65 , and an end cap 71 . These sections are held together in tight, sealing engagement by means of a plurality of bolts 73 , only one of which is shown in FIG. 3, and which are in threaded engagement with the housing 29 .
  • the housing 29 defines the inlet port 31 , the return port 33 , and the control ports 41 and 43 .
  • the housing 29 also defines the load signal port 37 which is not shown in FIG. 3.
  • the valving arrangement 61 comprises a primary, rotatable valve member 77 (hereinafter also the “spool”), and a cooperating, relatively rotatable follow-up valve member 79 (hereinafter also the “sleeve”).
  • a primary, rotatable valve member 77 hereinafter also the “spool”
  • a cooperating, relatively rotatable follow-up valve member 79 hereinafter also the “sleeve”.
  • a portion having a reduced diameter and defining a set of internal splines 81 which provide for a direct mechanical connection between the spool 77 and the steering wheel 63 .
  • the fluid meter 65 may be of a type well known in the art and includes herein, and by way of example only, an internally toothed ring 83 , and an externally toothed star 85 .
  • the star 85 defines a set of internal splines 87 , and in splined engagement therewith is a set of external splines 89 , formed at the rearward end of a main drive shaft 91 .
  • the shaft 91 has a bifurcated forward end permitting driving connection between the shaft 91 and the sleeve 77 , by means of a pin 93 passing through a pair of pin openings 95 in the spool 77 .
  • pressurized fluid flowing through the valving 61 in response to rotation of the steering wheel 63 and the spool 77 flows through the fluid meter 65 , causing orbital and rotational movement of the star 85 within the ring 83 .
  • Such movement of the star 85 causes follow-up movement of the sleeve 79 , by means of the drive shaft 91 and pin 93 (which together comprise the follow-up connection 67 of FIGS. 1 and 2).
  • This movement of the star 85 maintains a particular relative displacement between the spool 77 and sleeve 79 , for a given, constant rate of rotation of the steering wheel.
  • a plurality of leaf springs 97 extends through an opening in the sleeve 79 , biasing the sleeve 79 toward its neutral position relative to the spool 77 , in a manner which is conventional and well known in the art.
  • the housing 29 defines four annular chambers surrounding the sleeve 79 , to provide fluid communication between the outer surface of the sleeve 79 and the various ports 31 , 33 , 41 and 43 .
  • the various annular chambers are designated by the reference numeral of the respective port, accompanied by the letter “c”. Those skilled in the art will understand the interaction of the annular chambers 31 c , 33 c , 41 c and 43 c with the valving 61 .
  • FIGS. 4 and 5 illustrate the spool 77 and the sleeve 79 will be described in greater detail.
  • FIG. 4 illustrates the outer surface of the spool 77
  • FIG. 5 illustrates both the outer surface of the sleeve 79 and several features which are disposed on the inner surface of the sleeve 79 , and therefore, are in a valving relationship with the features disposed on the outer surface of the spool 77 .
  • both the spool 77 and the sleeve 79 include a number of features or elements which are conventional, but are not directly involved in the operation of the invention, and therefore, do not bear reference numerals in FIGS. 4 and 5, are not described hereinafter.
  • the spool 77 defines an annular groove 101 , and in communication therewith, a plurality of axial slots 103 . Circumferentially displaced from each of the axial slots 103 is a longer axial slot 105 , and circumferentially aligned with each of the axial slots 103 is an even longer axial slot 107 , the function of which will be described subsequently.
  • the spool 77 defines a plurality of axial, open-center slots 109 , each of which has, adjacent thereto, a slot 111 which is in open communication, toward its right end, with the interior of the spool 77 .
  • the sleeve 79 defines a plurality of pressure ports 113 , in communication with the annular chamber 31 c and therefore, the pressure ports 113 receive pressurized, un-metered fluid from the source 11 .
  • To the left of the ports 113 is a plurality of meter ports 115 , which communicate between the valving arrangement 61 and the expanding and contracting fluid volume chambers of the fluid meter 65 , through the axial bores defined by the housing 29 , in a manner well know to those skilled in the art.
  • the star 85 has six external teeth and the ring 83 has seven internal teeth, so there are 12 of the meter ports 115 .
  • a plurality of cylinder ports 117 Disposed to the left of the meter ports 115 is a plurality of cylinder ports 117 , in communication with the annular chamber 41 c , and further to the left, a plurality of cylinder ports 119 , in communication with the annular chamber 43 c.
  • FIGS. 6 - 8 are enlarged (relative to FIGS. 4 and 5), and are fragmentary overlay views of the spool 77 (except where visible through an opening in the sleeve 79 ) and the sleeve 79 (but showing only those features present on the inside surface of the sleeve).
  • inlet fluid is communicated from the inlet port 31 into the annular chamber 31 c .
  • the pressure ports 113 are in open communication with the annular chamber 31 c , but there is no flow through the pressure port 113 , because, in the neutral position shown in FIG. 6, the ports 113 are blocked from communication with any of the slots or grooves defined by the spool 77 , i.e., the ports 113 are blocked by the outer cylindrical surface of the spool 77 .
  • each of the axial slots 103 begins to communicate with one of the meter ports 115 , the area of overlap therebetween defining a variable orifice, and the composite of these comprising a variable flow control orifice A 2 , as is well known to those skilled in the art and is not shown in the schematics of FIGS. 1 and 2.
  • Every other meter port 115 is in communication with one of axial slots 103 , while the alternate meter ports 115 are now in communication with the longer axial slots 105 .
  • the area of overlap between each of these alternate meter ports 115 and the respective axial slots 105 defines a variable orifice, and the composite of these comprises a variable flow control orifice A 3 , also not shown in the schematics of FIGS. 1 and 2.
  • the fluid which flows through the A 2 orifice, and from there to the expanding volume chambers of the fluid meter 65 is pressurized, un-metered fluid, while the fluid which flows from the contracting volume chambers of the fluid meter 65 through the A 3 orifice is pressured, metered fluid.
  • each of the longer axial slots 105 begins to communicate with an adjacent one of the cylinder ports 117 , the overlap therebetween defining a variable orifice, and the composite of these individual orifices comprising a variable flow control orifice A 4 .
  • the cylinder ports 117 are in communication, by means of the annular chamber 41 c , with the control fluid port 41 , and with what is, in a right turn condition, the inlet 47 of the rotary motor 45 .
  • variable flow control orifices A 2 and A 3 i.e., those on the inlet and outlet sides, respectively, of the fluid meter 65 .
  • the A 2 and A 3 orifices are fixed orifices, rather than variable. All that is required for the present invention is to have one flow control orifice (e.g., the Al orifice) between the inlet port 31 and the fluid meter 65 , and one more flow control orifice (e.g., A 4 ) between the fluid meter 65 and the control (motor) fluid port 41 or 43 .
  • valving 61 has a maximum deflection (displacement) of about 10 degrees. Therefore, as the valving 61 approaches the maximum displacement position (R-M in FIG. 2), i.e., when the relative displacement of the spool and sleeve is about 9 degrees (the position shown in FIG. 8) the various flow control orifices A 1 through A 5 have reached, or nearly reached, their maximum flow area.
  • the pressure ports are labeled 113 -R and 113 -L.
  • the pressure port 113 -R is the one which overlaps the axial slot 103 to define the A 1 orifice in a right turn condition
  • the pressure port 113 -L is one the which moves away from its respective axial slot 103 , but would overlap its respective axial slot 103 to form the Al orifice in a left turn condition.
  • the pressure port 113 -L begins to overlap the respective axially extending recess 121 , the area of overlap therebetween defining a variable orifice, and the composite of the three overlaps (because there are three of the recesses 121 ) comprises a variable bleed orifice A B .
  • the fluid bleed passage including the variable lead orifice A B has an upstream portion in communication with the main fluid path at a location upstream of the first variable fluid control orifice A 1 , and a downstream portion in communication with the main fluid path downstream of the fluid meter 65 , but upstream (preferably) of the variable flow control orifice A 4 .
  • the flow control orifice A 4 is shown schematically as a fixed orifice, purely for ease of illustration.
  • a sufficient quantity of fluid is communicated through the fluid bleed passage, and through the variable bleed orifice A B , and joins the fluid which flows through the main fluid path of the fluid controller 27 , this combination of the main path fluid and the bleed fluid together flowing to the control port 43 , and from there to the inlet of the rotary motor 45 .

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Power Steering Mechanism (AREA)
US09/870,024 2001-05-30 2001-05-30 Low slip steering system and improved fluid controller therefor Abandoned US20020179161A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US09/870,024 US20020179161A1 (en) 2001-05-30 2001-05-30 Low slip steering system and improved fluid controller therefor
EP20020011954 EP1262393B1 (de) 2001-05-30 2002-05-29 Lenksystem mit geringer Lenk-Abweichung und verbessertem Fluid-Regler dafür
JP2002155851A JP4122473B2 (ja) 2001-05-30 2002-05-29 スリップを低減したステアリングシステムに用いる流体制御器
DE2002607927 DE60207927T2 (de) 2001-05-30 2002-05-29 Lenksystem mit geringem Schlupf und verbessertem Fluidsteuergerät
US10/278,953 US6769249B2 (en) 2001-05-30 2002-10-23 Low slip steering system and improved fluid controller therefor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US09/870,024 US20020179161A1 (en) 2001-05-30 2001-05-30 Low slip steering system and improved fluid controller therefor

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US10/278,953 Continuation-In-Part US6769249B2 (en) 2001-05-30 2002-10-23 Low slip steering system and improved fluid controller therefor

Publications (1)

Publication Number Publication Date
US20020179161A1 true US20020179161A1 (en) 2002-12-05

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US09/870,024 Abandoned US20020179161A1 (en) 2001-05-30 2001-05-30 Low slip steering system and improved fluid controller therefor
US10/278,953 Expired - Lifetime US6769249B2 (en) 2001-05-30 2002-10-23 Low slip steering system and improved fluid controller therefor

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Application Number Title Priority Date Filing Date
US10/278,953 Expired - Lifetime US6769249B2 (en) 2001-05-30 2002-10-23 Low slip steering system and improved fluid controller therefor

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US (2) US20020179161A1 (de)
EP (1) EP1262393B1 (de)
JP (1) JP4122473B2 (de)
DE (1) DE60207927T2 (de)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7028469B2 (en) * 2002-10-08 2006-04-18 Sauer-Danfoss Aps Leakage compensation arrangement in a control device for a fully hydraulic steering system
US7610935B2 (en) * 2005-06-10 2009-11-03 Sauer-Danfoss Aps Fluid controller
US7490626B2 (en) * 2005-10-07 2009-02-17 Eaton Corporation Steer valve with hydraulic vehicle position feedback
EP2127998A1 (de) 2008-05-30 2009-12-02 Sauer-Danfoss Holding ApS Hydraulische Lenkeinheit
US9238479B2 (en) * 2010-05-21 2016-01-19 Eaton Corporation Steering system with dynamic slip reduction
KR102251791B1 (ko) 2018-10-26 2021-05-13 주식회사 엘지화학 폴리아릴렌 설파이드의 제조 방법

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4558720A (en) * 1983-03-17 1985-12-17 Eaton Corporation Closed-center controller for use with unequal area cylinder
US4663936A (en) * 1984-06-07 1987-05-12 Eaton Corporation Load sensing priority system with bypass control
US4781219A (en) * 1986-10-10 1988-11-01 Eaton Corporation Fluid controller and dampening fluid path
US4759182A (en) * 1987-07-24 1988-07-26 Eaton Corporation Steering control unit with flow amplification
US4827978A (en) * 1988-10-03 1989-05-09 Eaton Corporation Fluid controller with reduced steering wheel precession
US4862690A (en) * 1988-10-06 1989-09-05 Eaton Corporation Steering control unit with both flow amplification and manual steering capability
US5136844A (en) * 1990-10-11 1992-08-11 Eaton Corportaion Controller with reduced travel limit slip
US5638864A (en) * 1995-11-22 1997-06-17 Eaton Corporation Steering control unit with flow amplification for unequal area cylinder

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Publication number Publication date
JP4122473B2 (ja) 2008-07-23
DE60207927D1 (de) 2006-01-19
EP1262393A2 (de) 2002-12-04
JP2003026015A (ja) 2003-01-29
DE60207927T2 (de) 2006-07-20
US6769249B2 (en) 2004-08-03
EP1262393B1 (de) 2005-12-14
US20030037827A1 (en) 2003-02-27
EP1262393A3 (de) 2003-05-07

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AS Assignment

Owner name: EATON CORPORATION, OHIO

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:NOVACEK, WILLIAM J.;REEL/FRAME:012250/0905

Effective date: 20010904

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE